Acute exacerbation of fibrotic hypersensitivity pneumonitis: incidence and outcomes

Abstract

Background Patients with fibrotic hypersensitivity pneumonitis (HP) show variable clinical courses, and some experience rapid deterioration (RD), including acute exacerbation (AE). However, little is known about AE in fibrotic HP. Here, we retrospectively examined the incidence, risk factors, and outcomes of AE in fibrotic HP. Methods The incidence rates of AE were calculated in 101 patients with biopsy-proven HP. AE was defined as the worsening of dyspnoea within 30 days, with new bilateral lung infiltration and no evidence of infection or other causes of dyspnoea. Results During follow-up (median: 30 months), 18 (17.8%) patients experienced AE. The 1, 3, and 5 year incidence rates of AE were 6.0, 13.6, and 22.8%, respectively. Lower diffusing capacity of the lung for carbon monoxide (DLCO) and a radiologic usual interstitial pneumonia (UIP)-like pattern were risk factors for AE. In-hospital mortality after AE was 44.4%. Median survival from diagnosis was significantly shorter in patients with AE (26.0 months) than in those with no-AE RD (55.0 months; p = 0.008) or no RD (not reached; p < 0.001). AE remained a significant predictor of all-cause mortality (hazard ratio, 8.641; 95% confidence interval, 3.388–22.040; p < 0.001) after adjustment for age, body mass index, lung function, lymphocyte levels in bronchoalveolar lavage fluid, and the presence of a UIP-like pattern. Conclusions AE was not uncommon among patients with fibrotic HP and significantly affected prognosis. A lower DLCO value and radiologic UIP-like pattern at diagnosis were associated with the development AE in patients with fibrotic HP.

Hypersensitivity Pneumonitis: Diagnostic and Therapeutic Challenges

“…Several studies have reported acute exacerbation (AE) in patients with fibrotic HP, following the same definition used in IPF, which results in poor prognosis ( 61 ). Recently it was reported as risk factors lower DLco, the presence of UIP-like pattern on HRCT at diagnosis, and cumulative incidence rates of AE showed high in-hospital mortality rate ( 62 ).…”

Challenges in the Diagnosis and Management of Fibrotic Hypersensitivity Pneumonitis: A Practical Review of Current Approaches

“…Only a few studies have differentiated survival outcomes based on histologic subtype [ 107 ], with those having UIP-like findings and less cellularity and granuloma formation having poorer outcomes [ 71 ]. Lastly, acute exacerbation characterized by punctuated decline over several weeks with worsening clinical and radiologic findings has been reported in f-HP [ 111 ], occurring in up 18% over a median follow-up of 30 months with an in-hospital mortality of 44% in one series [ 112 ].…”

Hypersensitivity pneumonitis: Current concepts in pathogenesis, diagnosis, and treatment

“…Patients may also present with acute exacerbations (acute respiratory deterioration with new ground‐glass opacities on CT, not due to any other cause), with or without re‐exposure to the inciting antigen. Similar to other fibrotic ILDs, HP exacerbations are more common in those with a UIP‐like pattern and portend poor survival 64,65 …”